CA2282219C - Fluorescent lamp - Google Patents
Fluorescent lamp Download PDFInfo
- Publication number
- CA2282219C CA2282219C CA002282219A CA2282219A CA2282219C CA 2282219 C CA2282219 C CA 2282219C CA 002282219 A CA002282219 A CA 002282219A CA 2282219 A CA2282219 A CA 2282219A CA 2282219 C CA2282219 C CA 2282219C
- Authority
- CA
- Canada
- Prior art keywords
- discharge tube
- fluorescent lamp
- electrode
- thermally conducting
- conducting material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/70—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr
- H01J61/72—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr having a main light-emitting filling of easily vaporisable metal vapour, e.g. mercury
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/30—Vessels; Containers
- H01J61/35—Vessels; Containers provided with coatings on the walls thereof; Selection of materials for the coatings
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/52—Cooling arrangements; Heating arrangements; Means for circulating gas or vapour within the discharge space
- H01J61/523—Heating or cooling particular parts of the lamp
Landscapes
- Vessels And Coating Films For Discharge Lamps (AREA)
- Discharge Lamps And Accessories Thereof (AREA)
Abstract
The invention relates to a fluorescent lamp 1 for exterior lighting having a discharge tube 2 of less than or equal to 26 mm outside diameter. Starting from a fluorescent lamp for interior use having a discharge tube 2 of less than or equal to 26 mm, it is possible to achieve optimum operation of the fluorescent lamp 1 in the case of exterior use by applying a thermally conducting material in the form of a coating of foil 15, 16 outside on the discharge tube 2 in the region of one or both electrodes 3, 4.
Description
Fluorescent lamp Technical field The invention proceeds from a fluorescent lamp in accordance with the preamble of claim 1.
Prior art In the case of the known fluorescent lamps with outside tube diameters of greater than 26 mm, such as the T12 lamps with 38 mm, for example, the temperature of the cold spot at which the excess mercury condenses and which ensures an optimum luminous flux during operation of the lamp, is designed for an ambient temperature of approximately 25 C. The cold spot is situated in this case in the middle of the discharge tube on the inner glass wall.
In the case of the new fluorescent lamps with outside tube diameters of less than or equal to 26 mm (T8, T5), which have been developed specifically for interior lighting (ambient temperature of greater than 25 C), the temperature of the cold spot must be approximately 40 C so that an optimum light yield is. achieved. This is reached at an ambient temperature of approximately 35 C. With decreasing inside diameter, it is necessary to displace the cold spot from the middle of the lamp to a point behind the electrodes, since because of the ever increasing current density it is no longer possible to reach such a low temperature of approximately 40 C in the middle of the discharge tube.
For this purpose, one electrode is displaced further into the discharge tube by the formation of a longer stem seal, so that a cold spot of approximately 40 C
can form behind this electrode.
Prior art In the case of the known fluorescent lamps with outside tube diameters of greater than 26 mm, such as the T12 lamps with 38 mm, for example, the temperature of the cold spot at which the excess mercury condenses and which ensures an optimum luminous flux during operation of the lamp, is designed for an ambient temperature of approximately 25 C. The cold spot is situated in this case in the middle of the discharge tube on the inner glass wall.
In the case of the new fluorescent lamps with outside tube diameters of less than or equal to 26 mm (T8, T5), which have been developed specifically for interior lighting (ambient temperature of greater than 25 C), the temperature of the cold spot must be approximately 40 C so that an optimum light yield is. achieved. This is reached at an ambient temperature of approximately 35 C. With decreasing inside diameter, it is necessary to displace the cold spot from the middle of the lamp to a point behind the electrodes, since because of the ever increasing current density it is no longer possible to reach such a low temperature of approximately 40 C in the middle of the discharge tube.
For this purpose, one electrode is displaced further into the discharge tube by the formation of a longer stem seal, so that a cold spot of approximately 40 C
can form behind this electrode.
Since these lamps have been very well received because of their high light yield and their slim finish, it was of interest also to make use of these lamps in exterior lighting (ambient temperatures of less than 25 C). However, the temperature of the cold spot behind the electrode is not designed for this purpose, with the result that it is not possible to achieve optimum light yields with these lamps.
Summary of the Invention It is the object of the present invention to provide a fluorescent lamp having a discharge tube with an outside diameter of less than or equal to 26 mm which ensures an optimum light yield even in the case of exterior operation with relatively cold ambient temperatures of less than 25 C. It should be possible to achieve the object using simple means, and there should be no fundamental changes to the lamp design as a result.
In one broad aspect, there is provided a fluorescent lamp for exterior lighting comprising a straight or circularly bent discharge tube made from glass with a circular cross section of less than or equal to 26 mm outside diameter, an electrode sealed into each end of the discharge tube, one electrode being arranged at a somewhat greater distance from the end of the discharge tube than the other electrode so that a cold spot can form behind this electrode, a fluorescent coating on the inner wall of the discharge tube and a mercury-inert gas filling as well as a base fitted respectively at either end of the discharge tube and having at least one base pin and a base shell wherein at least in the region of one electrode sealed at a somewhat greater distance from the end of the discharge tube a material which is a good conductor of heat is provided outside on the discharge tube.
2a By providing a material which is a good conductor of heat in the region of the electrode displaced further into the discharge tube, the heat in the glass tube in the region of this electrode can be directed toward the base.
As a result, the cold spot is displaced from a point behind the electrode into the middle of the lamp again, where it then acquires an optimum temperature because of the lower outside temperatures of less than 25 C.
The thermally conducting material preferably consists of a thermally conducting coating on the outer wall of the discharge tube, or of a thermally conducting foil which surrounds the discharge tube in this region over the entire outer circumference. Such a thermally conducting material is also preferably applied or provided outside on the glass tube in the region of the other sealed electrode.
For optimum heating, the thermally conducting material should reach at least from the electrode filament to the edge of the base shell. It is even better if the thermally conducting material reaches beyond the electrode filament in the direction of the middle of the glass tube and - in the case of a foil - is soldered or welded to the case shell. In the case of a thermally conducting foil, the latter preferably contains aluminum or copper.
Description of the drawings The invention is explained in more detail below with the aid of an exemplary embodiment.
A straight fluorescent lamp 1 in accordance with the invention is reproduced in the figure in a partially sectioned and shortened form. The fluorescent lamp 1 with a power consumption of 54 W has a discharge tube 2 made from glass with an outside diameter of 16 mm and a length of 1 150 mm, and in each of its ends an electrode 3, 4 is respectively sealed on a stem 5, 6.
The stem 5 of one electrode 3 is 20 mm longer in this case, with the result that the filament 7 of one electrode 3 is 20 mm further from the associated end of the discharge tube 2 than the filament 8 of the other electrode 4. The bases 9, 10 with base shells 11, 12 and base pins 13, 14 which are electrically connected to the electrodes 3, 4 are applied to the two ends of the discharge tube 2. The fluorescent lamp 1 also has a fluorescent coating on the inside of the discharge tube 2 which is not represented - because of clarity.
Summary of the Invention It is the object of the present invention to provide a fluorescent lamp having a discharge tube with an outside diameter of less than or equal to 26 mm which ensures an optimum light yield even in the case of exterior operation with relatively cold ambient temperatures of less than 25 C. It should be possible to achieve the object using simple means, and there should be no fundamental changes to the lamp design as a result.
In one broad aspect, there is provided a fluorescent lamp for exterior lighting comprising a straight or circularly bent discharge tube made from glass with a circular cross section of less than or equal to 26 mm outside diameter, an electrode sealed into each end of the discharge tube, one electrode being arranged at a somewhat greater distance from the end of the discharge tube than the other electrode so that a cold spot can form behind this electrode, a fluorescent coating on the inner wall of the discharge tube and a mercury-inert gas filling as well as a base fitted respectively at either end of the discharge tube and having at least one base pin and a base shell wherein at least in the region of one electrode sealed at a somewhat greater distance from the end of the discharge tube a material which is a good conductor of heat is provided outside on the discharge tube.
2a By providing a material which is a good conductor of heat in the region of the electrode displaced further into the discharge tube, the heat in the glass tube in the region of this electrode can be directed toward the base.
As a result, the cold spot is displaced from a point behind the electrode into the middle of the lamp again, where it then acquires an optimum temperature because of the lower outside temperatures of less than 25 C.
The thermally conducting material preferably consists of a thermally conducting coating on the outer wall of the discharge tube, or of a thermally conducting foil which surrounds the discharge tube in this region over the entire outer circumference. Such a thermally conducting material is also preferably applied or provided outside on the glass tube in the region of the other sealed electrode.
For optimum heating, the thermally conducting material should reach at least from the electrode filament to the edge of the base shell. It is even better if the thermally conducting material reaches beyond the electrode filament in the direction of the middle of the glass tube and - in the case of a foil - is soldered or welded to the case shell. In the case of a thermally conducting foil, the latter preferably contains aluminum or copper.
Description of the drawings The invention is explained in more detail below with the aid of an exemplary embodiment.
A straight fluorescent lamp 1 in accordance with the invention is reproduced in the figure in a partially sectioned and shortened form. The fluorescent lamp 1 with a power consumption of 54 W has a discharge tube 2 made from glass with an outside diameter of 16 mm and a length of 1 150 mm, and in each of its ends an electrode 3, 4 is respectively sealed on a stem 5, 6.
The stem 5 of one electrode 3 is 20 mm longer in this case, with the result that the filament 7 of one electrode 3 is 20 mm further from the associated end of the discharge tube 2 than the filament 8 of the other electrode 4. The bases 9, 10 with base shells 11, 12 and base pins 13, 14 which are electrically connected to the electrodes 3, 4 are applied to the two ends of the discharge tube 2. The fluorescent lamp 1 also has a fluorescent coating on the inside of the discharge tube 2 which is not represented - because of clarity.
In this respect, this fluorescent lamp 1 according to the invention corresponds to a fluorescent lamp for interior use, a cold spot with a temperature of 40 C
being formed at an ambient temperature of approximately 35 C during interior operation behind the electrode filament 7 on the longer stem 5, and thereby ensuring optimum emission of luminous flux.
According to the invention, the two ends of a discharge tube 2 are tightly surrounded by a sleeve made from a copper-aluminum foil 15, 16 of thickness approximately 0.1 mm, which starts 5 mm(seen from the middle of the discharge tube 2 in the direction of the end) before the respective electrode filament 7, 8, and overlaps the base shell 11, 12 by about 5 mm.
These additional foil sleeves 15, 16 create a fluorescent lamp for exterior use from a fluorescent lamp for interior use. During operation, the foil sleeves 15, 16 ensure strong heating of the interior behind the electrode filaments 7, 8, with the result that the cold spot now forms in the middle of the discharge tube 2 on the inner wall. In the case of exterior use with an ambient temperature of approximately 5 C, during operation the cold spot assumes a temperature of approximately 40 C, with the result that an optimum emission of luminous flux is set up at this outside temperature.
being formed at an ambient temperature of approximately 35 C during interior operation behind the electrode filament 7 on the longer stem 5, and thereby ensuring optimum emission of luminous flux.
According to the invention, the two ends of a discharge tube 2 are tightly surrounded by a sleeve made from a copper-aluminum foil 15, 16 of thickness approximately 0.1 mm, which starts 5 mm(seen from the middle of the discharge tube 2 in the direction of the end) before the respective electrode filament 7, 8, and overlaps the base shell 11, 12 by about 5 mm.
These additional foil sleeves 15, 16 create a fluorescent lamp for exterior use from a fluorescent lamp for interior use. During operation, the foil sleeves 15, 16 ensure strong heating of the interior behind the electrode filaments 7, 8, with the result that the cold spot now forms in the middle of the discharge tube 2 on the inner wall. In the case of exterior use with an ambient temperature of approximately 5 C, during operation the cold spot assumes a temperature of approximately 40 C, with the result that an optimum emission of luminous flux is set up at this outside temperature.
Claims (8)
1. A fluorescent lamp for exterior lighting comprising a straight or circularly bent discharge tube made from glass with a circular cross section of less than or equal to 26 mm outside diameter, an electrode sealed into each end of the discharge tube, one electrode being arranged at a somewhat greater distance from the end of the discharge tube than the other electrode so that a cold spot can form behind this electrode, a fluorescent coating on the inner wall of the discharge tube and a mercury-inert gas filling as well as a base fitted respectively at either end of the discharge tube and having at least one base pin and a base shell wherein at least in the region of one electrode sealed at a somewhat greater distance from the end of the discharge tube a material which is a good conductor of heat is provided outside on the discharge tube.
2. The fluorescent lamp as claimed in claim 1, wherein in the region of the other sealed electrode as well, a material which is a good conductor of heat is provided outside on the discharge tube.
3. The fluorescent lamp as claimed in claim 1, wherein the thermally conducting material consists of a thermally conducting coating.
4. The fluorescent lamp as claimed in claim 1, wherein the thermally conducting material consists of a thermally conducting foil.
5. The fluorescent lamp as claimed in claim 1, wherein the thermally conducting material reaches at least from a filament of the electrode up to the inner edge of the base shell.
6 6. The fluorescent lamp as claimed in claim 5, wherein the thermally conducting material surrounds the discharge tube over the entire outer circumference.
7. The fluorescent lamp as claimed in claim 1, wherein the material is thermally conducting foil which contains at least one of aluminum and copper.
8. The fluorescent lamp as claimed in claim 3, wherein the thermally conducting material is one of soldered and welded to the base shell.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19842795A DE19842795A1 (en) | 1998-09-18 | 1998-09-18 | Fluorescent lamp |
| DE19842795.6 | 1998-09-18 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2282219A1 CA2282219A1 (en) | 2000-03-18 |
| CA2282219C true CA2282219C (en) | 2008-05-06 |
Family
ID=7881402
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002282219A Expired - Fee Related CA2282219C (en) | 1998-09-18 | 1999-09-15 | Fluorescent lamp |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US6359376B1 (en) |
| EP (1) | EP0987737B1 (en) |
| CA (1) | CA2282219C (en) |
| DE (1) | DE19842795A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2795553A1 (en) * | 1999-06-28 | 2000-12-29 | Koninkl Philips Electronics Nv | INCANDESCENT LAMP COMPRISING A TUBULAR SHAPE GLASS BULB IN WHICH A AXIS OF A FILAMENT IS ARRANGED |
| DE10120667B4 (en) * | 2001-04-27 | 2007-11-22 | Siteco Beleuchtungstechnik Gmbh | Lamp with a lamp with cooled cold foot |
| DE20307607U1 (en) * | 2003-05-15 | 2004-09-23 | Zumtobel Staff Gmbh | Lighting arrangement consisting of a gas discharge lamp and a shielding sleeve |
| US7279840B2 (en) | 2004-11-17 | 2007-10-09 | Matsushita Electric Works Ltd. | Electrodeless fluorescent lamp with controlled cold spot temperature |
| KR101157289B1 (en) * | 2005-06-30 | 2012-06-15 | 엘지디스플레이 주식회사 | Backlight assembly and liquid crystal display having the same |
| KR20070010844A (en) * | 2005-07-20 | 2007-01-24 | 삼성전자주식회사 | Surface light source device and display device having same |
| US7612491B2 (en) * | 2007-02-15 | 2009-11-03 | Applied Materials, Inc. | Lamp for rapid thermal processing chamber |
| WO2008142630A1 (en) * | 2007-05-24 | 2008-11-27 | Philips Intellectual Property & Standards Gmbh | Discharge lamp and headlights for a motor vehicle |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1915019A (en) * | 1931-09-08 | 1933-06-20 | Gen Electric | Gaseous electric discharge device |
| US2491854A (en) * | 1946-04-06 | 1949-12-20 | Gen Electric | Starting strip for electric discharge devices |
| NL245727A (en) * | 1958-11-25 | 1900-01-01 | ||
| HU176380B (en) * | 1978-05-12 | 1981-02-28 | Egyesuelt Izzolampa | Electric discharge tube,preferably high-pressure sodium vapour or metal halogen vapour lamp with outdoor applicability,with a device controlling the temperature distribution of the discharge space |
| SE8800747D0 (en) * | 1988-03-02 | 1988-03-02 | Lumalampan Ab | Low pressure gas discharge lamp |
| JPH067559Y2 (en) * | 1988-06-20 | 1994-02-23 | 旭光学工業株式会社 | Lamp lighting structure |
| JPH03114138A (en) * | 1989-09-28 | 1991-05-15 | Matsushita Electron Corp | Fluorescent lamp |
| US5952768A (en) * | 1994-10-31 | 1999-09-14 | General Electric Company | Transparent heat conserving coating for metal halide arc tubes |
| JPH0917383A (en) * | 1995-06-26 | 1997-01-17 | Matsushita Electric Works Ltd | Fluorescent lamp |
| US5680000A (en) * | 1995-11-07 | 1997-10-21 | Osram Sylvania Inc. | Reflective metal heat shield for metal halide lamps |
| EP0913628A3 (en) * | 1997-10-31 | 2001-05-16 | Toshiba Lighting & Technology Corporation | A lighting fixture |
| US5808418A (en) * | 1997-11-07 | 1998-09-15 | Honeywell Inc. | Control mechanism for regulating the temperature and output of a fluorescent lamp |
-
1998
- 1998-09-18 DE DE19842795A patent/DE19842795A1/en not_active Withdrawn
-
1999
- 1999-07-02 EP EP99112629A patent/EP0987737B1/en not_active Expired - Lifetime
- 1999-08-26 US US09/383,979 patent/US6359376B1/en not_active Expired - Fee Related
- 1999-09-15 CA CA002282219A patent/CA2282219C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2282219A1 (en) | 2000-03-18 |
| EP0987737A1 (en) | 2000-03-22 |
| EP0987737B1 (en) | 2013-01-09 |
| DE19842795A1 (en) | 2000-03-23 |
| US6359376B1 (en) | 2002-03-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20140916 |
